1. Field of the Invention
The present invention relates to a process for forming a polymer chain of monomers selected from the group consisting of hydrocarbyl radicals and functional group-containing monomers. The hydrocarbyl radicals contain unsaturation capable of polymerization by heterogeneous or homogeneous Ziegler catalysis. The formed polymer chain includes copolymers and terpolymers of ethylene and alpha-olefins formed principally, but not exclusively, by Ziegler polymerization mechanisms. The functional group-containing monomers include olefins with carboxyl, hydroxyl and amine groups. The polymer chain is composed of monomers of hydrocarbyl radicals and such functional group-containing monomers. The present invention also relates to a process for forming masked, functional group-containing monomers, and particularly masked carboxyl, hydroxyl and amine group-containing monomers, as well as the masked, carboxyl, hydroxyl and amine group-containing monomers. In addition the invention relates to reaction mixtures including monomers selected from the group consisting of hydrocarbyl radicals and members selected from the group consisting of masked, carboxylic acids, alcohols and amine group-containing monomers.
2. Discussion of Background and Material Information
Polymers prepared from alpha-olefins using Ziegler catalysts have found acceptance for use in a wide range of applications including elastomers, fibers and films. Inasmuch as the polymers are essentially nonpolar, however, they have a characteristic inertness which makes them difficult to surface treat, for example, by dyeing or metallizing techniques. Additionally, they are limited in the amount of additives, such as stabilizers and plasticizers which they can accommodate without "blooming". Similar limitations are found in the rubbery copolymers and terpolymers produced from alpha-olefins.
In an attempt to overcome these disadvantages, efforts have been made to introduce polar functional groups into such polyolefins, both homo and copolymers. Previous efforts in this direction have included both the direct incorporation of functionalized monomers during the polymerization process as well as post-polymerization functionalization of polymers.
Post-polymerization techniques for the treatment of olefin polymers to introduce polar groups are well known. For example, the polymer may be oxidized or it may be irradiated with subsequent contacting of the polymer with an unsaturated polar monomer. Similarly, methods of sulfonating the olefin polymers are well known. Among other things, however, these techniques are costly because they require additional treatment and recovery steps after polymerization.
Efforts have been made to incorporate polar monomers directly into the polymer using various techniques. U.S. Pat. No. 3,492,277 discloses a method for forming a complex of a polar monomer containing a labile hydrogen, as in --NH.sub.2, --COOH, or --OH, by contacting the polar monomer in an inert hydrocarbon solvent with an organoaluminum compound at a molar ratio of polar monomer to organoaluminum compound of from 1:1 to 1:3, and then heating the solution to between 60.degree. and 150.degree. C. The organic aluminum compounds disclosed have the general formulas AlR.sub.1 R.sub.2 R.sub.3 or AlR.sub.1 R.sub.2 X' wherein R.sub.1, R.sub.2 and R.sub.3 are the same or different alkyl or aryl radicals and X' is either chlorine or bromine. The method disclosed is alleged to be useful with a wide range of monomers including those having polar groups such as --COOR', --CHO, --SH and --SO.sub.3 H. The polar monomers have the general formula: ##STR1## wherein n is an integer greater than 2, R is hydrogen, an alkyl or aryl radical, and Z is the polar moiety. Z can also be an aromatic nucleus bearing such moieties. Although R.sub.1, R.sub.2 and R.sub.3 are generally described as being the same or different aryl or alkyl radicals, this patent does not disclose that non-halogenated organoaluminum compounds affect the results achieved and otherwise disclose and illustrate the procedure by way of examples wherein a halogenated organoaluminum compound is used.
Reaction of the organoaluminum compound with the polar monomer results in a polar monomer reaction product complex, e.g. 5-hydroxy-1-pentene and diethyl aluminum chloride ##STR2## with the elimination of an alkyl or aryl radical from the organoaluminum compound. The complex can then be combined with alpha-olefin and Ziegler catalyst (titanium trichloride) for the polymerization. The polymerization is carried out at about 60.degree. C. to about 100.degree. C. The ratio of the preferred aluminum compound, diethylaluminum chloride, to titanium trichloride is 10:1 to 1:1.
U.S. Pat. No. 4,423,196 discloses a method of incorporating acyclic polar monomers into an alpha-olefin copolymer using an aluminum compound of the formula AlR.sub.n X'.sub.(3-n) wherein R is a C.sub.1 -C.sub.18 alkyl group, X' is halogen and 0&lt;n.ltoreq.3. The polar monomer is contacted at room temperature with one mole of organoaluminum compound, and then allowed to react for 1 hour at 70.degree. C. Polymerization is carried out using TiCl.sub.3 as the Ziegler catalyst, the ratio of organoaluminum to TiCl.sub.3 is 1:1 to 100:1. Polymerization is carried out at about 20.degree. C. to 100.degree. C. and preferably about 60.degree. C. to 90.degree. C. Illustrative of the polar monomers disclosed are eugenol and undec-1-enoic acid. The disclosure of EPO patent application No. 0 014 822 is similar in scope, but also discloses ethylene as a compound considered to be an alpha-olefin.
Matsumura, K. and Fukumoto, O., J. Pol. Sci., 9, 471-483 (1971) discloses the copolymerization of propylene using a Ziegler-Natta type catalyst (equimolar quantities of TiCl.sub.3 and triethyl aluminum) in the presence of ethylchloroaluminum acrylate, which was formed by the reaction of acrylic acid with diethyl aluminum chloride under N.sub.2 at room temperature with cooling.
An article by Spevak, L. L.; Ivanochev, S. S.; et al entitled, "Copolymerization of Ethylene with Acrylic Acid and Its Derivatives Using the Catalyst System Al(C.sub.2 H.sub.5).sub.2 ClVO(OC.sub.2 H.sub.5).sub.3 " (Sci.-Ind. Enterp. "Plastpolim", Leningrad, USSR), Plaste Kautsch, 29(1), 12-15, 1982, discloses the preparation of ethylene/acrylic acid copolymers. An excess of organo aluminum compound is utilized both to complex the acrylic acid and to act as a cocatalyst for the AlEt.sub.2 ClVO(OEt).sub.3 polymerization catalyst system. Complexing of the acrylic acid is accomplished in situ during the polymerization process.
U.S. Pat. No. 3,796,687 discloses the preparation of ethylene--alpha-olefin--nonconjugated diene terpolymers using as a fourth monomer a polar compound of the formula: CH.sub.2 .dbd.CH--(CH.sub.2).sub.n --Y wherein n is an integer from 0 to 20 and Y is a functional group which can be ##STR3## and--SO.sub.2 Cl wherein R is H, alkyl, aryl or cycloalkyl containing 1 to 18 carbon atoms and R.sub.1 is either R or OR. Other polar compounds disclosed include bridged ring compounds (substituted norbornene) and substituted aromatic compounds. The substituents include those described above as well as alcohols. The polymerization catalyst comprises a vanadium compound and an organoaluminum cocatalyst in conjunction with a halogenated compound (e.g., hexachloropropylene) as catalyst reactivator. The ratio of aluminum compound to vanadium compound is at least 2:1 preferably 10:1. The polymerization is conducted by dissolving ethylene and a comonomer alpha-olefin in the reaction solvent, the alkylaluminum compound is then added, followed by addition of the unsaturated functional monomer and any diene, then any catalst reactivator, and finally the the vanadium compound.
U.S. Pat. Nos. 3,884,888, 3,901,860, and 4,017,669 are related to U.S. Pat. No. 3,796,687 and have substantially the same disclosures. U.S. Pat. No. 3,884,888 is directed to EPDM which contains as a fourth monomer, a bridged ring compound, e.g., norbornene substituted with a group defined as being --(CH.sub.2).sub.n --Z where n is 0 to 20 and Z is --NH.sub.2, --COOH, ##STR4## and --CN.
U.S. Pat. No. 3,901,860 is directed toward EPDM wherein the substituent is similar to that of U.S. Pat. No. 3,884,888 except that Z is COOH. U.S. Pat. No. 4,017,669 claims as the fourth monomer the same bridged ring structure of U.S. Pat. No. 3,884,885 and U.S. Pat. No. 3,901,860 except that the substituent is --(CH.sub.2).sub.n --COOR, wherein n is 0-20 and R can be alkyl, aryl, or cycloalkyl.
Japanese Patent No. JA 7337756-R discloses the copolymerization of an alpha-olefin with an unsaturated carboxylic acid of the formula CH.sub.2 .dbd.CH--(CH.sub.2).sub.n --COOH. The polymerization catalyst is a halide of Ti or V and an organoaluminum compound. The organoaluminum compound can be of the formula R.sub.3 Al, R.sub.2 AlX, RAlX.sub.2 R.sub.2 AlOR', RAl(OR')X and R.sub.3 Al.sub.2 X.sub.3 where R and R' are alkyl or aryl and X is halogen. The polymerization is effected at 0.degree.-130.degree. C. and 0-50 atmospheres. There is no prereaction of the aluminum compound with the carboxylic acid compound.
U.S. Pat. No. 3,761,458 discloses a process applicable to alpha-olefin containing polar monomers in which the polar groups are separated from the alpha-olefin by two or more carbon atoms. The polar monomer can contain more than one polar group. The polar group can be one of the amino, cyano, phosphine, (hydrocarb)oxy, metal--metalloid--containing groups, as well as metal salts of acid groups such as --COOH, --SO.sub.3 H, --PO(OR)OH, carboxyl groups, or hydrocarbyl sulfide groups. An essential component of the catalyst system is the halide or alkoxyhalide of a transition metal e.g., TiCl.sub.3. The preferred cocatalyst is an aluminum alkyl. Other catalysts include vanadium trichloride, zirconium tetrachloride etc. The aluminum compound has the formula AlR.sub.3 or RR'AlX wherein R is hydrocarbyl, R' is H or hydrocarbyl and X is halogen, H, alkoxy, aryloxy etc. All monomers and catalyst components are added to the reaction and there is no preference as to order of addition of the monomers. The preferred alkyl groups of the catalyst component is ethyl, but n-propyl, isopropyl, n-butyl, isobutyl, n-octyl or 2-ethyhexyl groups are taught as suitable.
U.S. Pat. No. 4,139,417 discloses amorphous copolymers of mono-olefins or of mono-olefins and non-conjugated dienes with unsaturated derivatives of imides. The polymer comprises about 99.9 to 80 weight percent of non-polar units derived from at least two mono-olefins containing 2 to 18 carbon atoms, particularly ethylene and propylene, and optionally one more non-conjugated diene. In the preparation of the polymer the imide is complexed with a Lewis acid, e.g. alkylaluminum dihalides, aluminum trihalides, boron halides, nickel halides. It is indicated that the Lewis acid-imide complex has a higher stability than that of the reaction products which the non-saturated imide may form with components of the coordination catalyst system used for the copolymerization. The complex between the Lewis acid and the unsaturated imide may be formed before being introduced into the polymerization zone, by dissolving the imide and Lewis acid in an inert solvent maintained at -80.degree. C. to +80.degree. C. Catalyst systems which are disclosed as being particularly suitable for the preparation of the copolymers are formed by the association of an organoaluminum compound with titanium, vanadium, tungsten or zirconium derivatives e.g. halides or oxyhalides. The organoaluminum compound may have the formula EQU AlY.sub.n Cl.sub.(3-n)
wherein n is 1, 3/2, 2 or 3 and Y is a lower alkyl group, e.g., C.sub.2 -C.sub.6 alkyl, the aluminum compound being associated with a titanium halide, vanadium halide or vanadium oxyhalide.
Japanese patent application No. 188996/1982 (Laid Open No. 80413/1984; 5/9/84) discloses a process for preparing a copolymer of an olefin and a polar vinyl monomer which comprises copolymerizing an olefin with a complex of the polar vinyl monomer and a Lewis acid. The amount of Lewis acid is in excess of an equimolar amount of polar monomer. The Lewis acid is represented by the general formula R.sub.m MX.sub.n wherein R is a hydrocarbyl group; M is B, Al or Sn; X is halogen, and n is greater than zero. Illustrative of the Lewis acid are ethylaluminum dichloride, aluminum chloride, boron trichloride and tin chloride. The polar vinyl monomer is an ester of an unsaturated alcohol and an organic acid. The catalyst component used in the copolymerization process comprises magnesium, titanium, halogen and an electron donor. It is prepared by heating or copulverizing a combination of magnesium or a magnesium compound, a titanium compound and an electron donor.
Japanese patent application No. 152767/1982 (Laid Open No. 43003/1984, 5/19/84) is similar in scope to Japanese application No. 188997/1982. The catalyst of Japanese patent application No. 1532767/1982 however, comprises a reduced titanium tetrachloride with an organoaluminum compound activated by an electron donor such as ether, ester, amine and/or a halogen containing compound. Illustrative of halogen containing compounds are the tetrachlorides of titanium, silicon and tin; hydrogen halide, halogens and halogenated hydrocarbon.